Atmospheric pressure plasma deposition of silver nanoparticles on bark fabric for bacterial growth inhibition

Abstract

Plasma technology that operates at atmospheric pressure is increasingly used for surface modification of heat-sensitive materials to confer antibacterial properties. In this study, atmospheric pressure plasma jet (APPJ) system was used to deposit silver nanoparticles (AgNPs) for antibacterial application into bark fabric used in the Cordillera Region, Philippines. Plasma was produced by applying 15 kV to silver electrodes while the argon and oxygen gases were allowed to flow at 15 and 5 liters per minute (LPM), respectively. Characterization of plasma by optical emission spectroscopy (OES) suggests the formation of active plasma species. The observed surface roughness which consequently enhanced the adsorption of AgNPs was confirmed by scanning electron microscopy (SEM) and wavelength dispersive x-ray fluorescence (WDXRF) analyses. Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) results further revealed the removal of surface impurities as indicated by the production of carbon dioxide. Qualitative and quantitative antibacterial assays proved the efficiency of the samples in inhibiting the growth of bacteria namely Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The antibacterial efficiency of the samples proportionally increased with longer plasma treatment time. Atmospheric pressure plasma jet could serve as a promising deposition technique with potential application in the production of antibacterial fabrics.